Containers used for the shipping, storing, and delivery of liquids, such as therapeutic fluids or fluids used in other medical applications, are often fabricated from single-ply or multi-ply polymeric materials. The materials are typically in sheet form. Two sheets of these materials are placed in overlapping relation, and the overlapping sheets are bonded at their peripheries to define a chamber or pouch for containing the fluids. These types of bags are typically referred to as two-dimensional flexible containers, flat bags, or “pillow bags.” U.S. Pat. No. 4,968,624 issued to Bacehowski et al. and commonly assigned to the assignee of the present application, Baxter International Inc. (“Bacehowski”), discloses a large volume, two-dimensional flexible container. These types of bags can reach volumes as large as 600 liters.
While 600 liters is a significant volume for a flexible container, there has been an ever increasing need to provide flexible containers of even greater volumes. This has lead to the development of three-dimensional flexible containers, sometimes referred to as “cubic bags.”
In the design and use of three-dimensional flexible containers of such volumes, certain problems are encountered. The large volume of liquid held by the containers exerts a hydraulic force against seams of the container, which in an unsupported state, might be sufficient to cause failure of the container. Indeed, containers this large, when filled with water or some other liquid, can weigh over 3000 pounds. The forces associated with such liquid volumes can cause the container seams to fail or rupture, therefore causing leaks in the container. The liquid held by the container may not be a commodity solution but often a sterile, custom formulated solution. Accordingly, even a very small leak can be costly in that any seam rupture compromises sterility of the entire contents of the container. Also, a failure of a container seam can cause literally hundreds of liters of liquid to escape from the container. This is costly in replacing the lost liquid contents of the container. Clean-up costs are also encountered.
These large volume, three-dimensional flexible containers are not intended to be free standing, but rather, are designed to be supported by a rigid or semi-rigid support container commonly referred to as a box ornn tank. The box can be made of various materials, commonly stainless steel. The stainless steel material is naturally an optical obstruction from seeing into the box. Typically, an operator has to look down into the box from the top. The box may have an access door on a side wall to allow an operator to view the inside of the box. The door, however, is very small in size and cannot provide a full view of the flexible container within the box. The side walls may have a series of small sight openings to allow one to determine the level of liquid in the container. Similarly, however, these small sight openings do not allow a full view of the container within the box.
By necessity, the box and flexible container will have some interaction. It is desirable for the filled flexible container to transfer the load and associated forces from the contained liquid to the box, so that minimal loads (preferably zero) are carried by the flexible container material, especially the container seams. It is also desirable that the container seams be fully supported to prevent container failures due to “creep,” which refers to the loss of seal integrity due to low but continuous tensile forces.
Because of the size of the containers, it may be difficult to properly align the container within the box. While initially properly aligned, the flexible container may shift becoming misaligned during the container filling process. If misaligned, the container can have unwanted folds that do not properly expand when the bag is filled. Such container folds caused from misalignment can result in undue stress on the container seams leading to container failure.
For example, as the container is filled with liquid, the container inflates and conforms to the surrounding box. Ideally, the container conforms as close to the inner walls of the box as possible although pleating of the container can occur. At the appropriate time, the liquid is drained from the container wherein the container collapses. If the container is unsupported, it will tend to collapse in horizontal pleats. The pleats can trap liquid within the container thus preventing the container from being fully drained. In some cases, once the container is drained, the container has served its purpose and is then discarded. In other cases, the container may be refilled as part of a larger process. In these instances, a horizontal pleating of the container can restrict the desired realignment during the refilling process. This can result in poor orientation or loss of the effective volume of the container. It may also result in insufficient support of the container. Thus, it is also desirable to vertically support the container within the box to optimize the draining and filling processes. Vertical support of the container within the box is particularly important when filling the container a second time.
U.S. Pat. No. 5,988,422 is directed to a sachet for bio-pharmaceutical fluid products. While the sachet is a three-dimensional container, the container does not have optimal angular construction between sides of the container. This will impact how such a container can be supported in a surrounding box. Accordingly, optimal filling, draining, and re-filling of the container cannot be achieved.
Some large volume flexible containers often employ a rigid or semi-rigid tube used in the filling and draining of the container, often referred to as a “dip tube.” The dip tube is attached to the top of the container and extends downward to the bottom interior surface of the container. The dip tube supports the center portion of the top panel of the container during draining much like a tent post. In this configuration, the dip tube creates vertical pleats during draining of the container, and also allows a refilling deployment for the container.
The dip tube, however, has several disadvantages. First, the dip tube cannot orient the distal vertical surfaces of the container if the container foot print geometry is more complex than a circle. In addition, as the container is drained, the walls of the container converge towards the center essentially creating loads of compression on the non-compliant dip tube. These compressive forces can cause several problems. The dip tube itself can buckle under these forces. The seal between the dip tube and the top of the container can be compromised. A bottom portion of the dip tube can also rupture the bottom of the container. Using a dip tube structure also increases the cost the container system. In addition, dip tubes are also often accompanied by a container vent to allow incoming air to displace fluid instead of collapsing the container material. Finally, the dip tube also provides another potential mode of contamination ingress to the contents of the container. Thus, there remains a need for a vertical support system for the container within the box that addresses the needs of draining and refilling without the added complexity of dip tubes and vents.
These large volume containers are also typically equipped with one or more ports equipped with a port closure for accessing the fluid within the container. The container may have the port in a bottom panel that opens into the container. Oftentimes, the port closure includes a tube having one end connected to the port. Because the container is often used in medical and biotechnical applications, the port closure must include means for maintaining the other free end of the tube free from contamination. In other words, the free end of the tube must be equipped with a sterile closure that prevents potential contaminants from entering the tube and container. It is also desirable, however, to allow air to enter the container because it facilitates manipulation of the container during handling and installation.
There are two common approaches for providing a sterile closure at the free end of the tube. First, the free end of the tube can be sealed shut. In this application, the tubing must be selected from a thermoplastic material such as PVC or polyethylene that permits sealing of the material. This material can be heat sealed or sealed using other sealing energies such as radio frequency or ultrasonics. Using a silicone tube is desirable in the manufacturing process applications where the container is used. For example, a pump can be connected to the tubing for long periods of time so that the fluid can be pumped from the container. The silicone tubing also has the ability to withstand high temperatures, especially when the end of the tube is sterilized using steam in place (S.I.P.) methodologies. One problem that exists in using a sealed silicone tube, however, is that while providing a sterile closure, it does not facilitate the free passage of gases. Gas transfer (venting) is desirable to facilitate manipulation of the container during handling and installation. In addition, to access a container having a sealed tube, an operator must use a sharp implement such as a knife, blade or other cutting utensil to open the tube. This introduces an opportunity to contaminate the tube, and also poses a risk of injury to the operator.
The second approach for providing a sterile closure at the free end of the tube is to use a formed element such as an injection molded part or stainless steel coupling. The tubing is fitted to the part or coupling, and then the part or coupling is covered with another mating injection molded part or coupling. Similar to the sealed tube approach, such fittings provide a sterile closure but do not provide for gas transfer without loss of sterility. In addition, using injected molded parts or stainless steel couplings is costly.
The present invention is provided to solve these and other problems.